Spine - 2026-03-27 - Journal Article
Shifting Single-level Anterior and Lateral Lumbar Interbody Fusion to the Ambulatory Setting: Comparative Outcomes from a Large Matched Cohort Analysis.
Green CK, Wang JE, Novicoff W, Lockey SD
Topics
Key Takeaway
Outpatient single-level ALIF/LLIF demonstrated higher 5-year revision-free survival (log-rank P=0.007) and 40% lower median 90-day global reimbursements ($5,169 vs. $6,779) compared to matched inpatient controls.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This study compared complications, healthcare utilization, and cost between outpatient and inpatient single-level ALIF/LLIF using the PearlDiver database (2010–2022) with 1:1 matching on age, sex, and Elixhauser Comorbidity Index. Outpatient procedures had lower intraoperative and 90-day complication rates, lower 30- and 90-day ED visit and readmission rates (P<0.001 for all), and superior 5-year revision-free survival. Median day-of-surgery reimbursement was $743 lower and 90-day global reimbursement was $1,610 lower in the outpatient cohort.
Key Limitation
Claims-based matching on ECI cannot fully account for the clinical selection bias inherent in choosing outpatient surgery—healthier, more functional patients are systematically directed to ambulatory settings, likely inflating the apparent outcome advantage of outpatient care.
Original Abstract
STUDY DESIGN
Retrospective cohort study.
OBJECTIVE
To compare outcomes and healthcare utilization between single-level anterior lumbar interbody fusion (ALIF) or lateral lumbar interbody fusion (LLIF) performed in inpatient and outpatient settings.
SUMMARY OF BACKGROUND DATA
As healthcare costs continue to rise, there has been a corresponding increase in the number of spine surgeries performed in ambulatory surgery centers. ALIF/LLIF are among the most commonly performed minimally invasive lumbar spine procedures. Large-scale data reporting on outcomes following outpatient ALIF/LLIF remains limited.
METHODS
A retrospective review of the PearlDiver database was conducted, querying for single-level ALIF/LLIF from 2010 to 2022 stratified by service location. Inpatient and outpatient cohorts were matched 1:1 on age range, gender, and the Elixhauser Comorbidity Index (ECI). Outcomes assessed included intraoperative complications, 90-day medical and surgical complications, 30-day and 90-day emergency department (ED) visits and inpatient readmissions, day-of-surgery and 90-day global reimbursements, and five-year revision-free survival.
RESULTS
A total of 8,342 patients who underwent outpatient ALIF/LLIF were matched to 8,342 patients who underwent inpatient procedures. Inpatient ALIF/LLIFs were associated with significantly higher rates of intraoperative and 90-day postoperative complications. Patients in the outpatient group were less likely to present to the ED or require hospital readmission at both 30 and 90 days postoperatively (P<0.001 for all) and demonstrated higher revision-free survival at 5 years (log-rank P=0.007). Outpatient procedures were associated with significantly lower reimbursements on the day of surgery (Median [IQR]: $3,199 [$1,270-$6,402] vs. $3,942 [$1,694-$9,433], P<0.001) and within 90 days postoperatively (Median [IQR]: $5,169 [$2,535-$9,480] vs. $6,779 [$3,407-$15,034], P<0.001)).
CONCLUSION
Outpatient ALIF/LLIF procedures are associated with significantly lower rates of postoperative ED visits, hospital readmissions, and total reimbursements compared to inpatient ALIF/LLIF, without an increased risk of complications. These findings support the safety and cost-efficiency of outpatient ALIF/LLIF in appropriately selected patients.